From: Dexuan Cui <decui@microsoft.com>
To: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "driverdev-devel@linuxdriverproject.org" 
	<driverdev-devel@linuxdriverproject.org>,
        "olaf@aepfle.de" <olaf@aepfle.de>,
        "apw@canonical.com" <apw@canonical.com>,
        "jasowang@redhat.com" <jasowang@redhat.com>,
        KY Srinivasan <kys@microsoft.com>
Subject: RE: [PATCH] Drivers: hv: vmbus: fix init_vp_index() for reloading
 hv_netvsc
Thread-Topic: [PATCH] Drivers: hv: vmbus: fix init_vp_index() for reloading
 hv_netvsc
Thread-Index: AQHQ1PmqheOSVXJLH02lF9Q/ZJ1ZDp4ISkUg
Date: Wed, 12 Aug 2015 12:29:46 +0000
Message-ID: <df758dc5629e421cb6089e85516384e4@SIXPR30MB031.064d.mgd.msft.net>
References: <1439387326-32427-1-git-send-email-decui@microsoft.com>
In-Reply-To: <1439387326-32427-1-git-send-email-decui@microsoft.com>
Accept-Language: en-US
Content-Language: en-US
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 8BIT
MIME-Version: 1.0
SpamDiagnosticOutput: 1:23
SpamDiagnosticMetadata: NSPM
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Aug 2015 12:29:51.6445
 (UTC)
X-MS-Exchange-CrossTenant-Id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=72f988bf-86f1-41af-91ab-2d7cd011db47;Ip=[206.191.229.116];Helo=[064-smtp-out.microsoft.com]
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BLUPR03MB294
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 2096
Lines: 59

> From: devel [mailto:driverdev-devel-bounces@linuxdriverproject.org] On Behalf
> Of Dexuan Cui
> Sent: Wednesday, August 12, 2015 21:49
> To: gregkh@linuxfoundation.org; linux-kernel@vger.kernel.org; driverdev-
> devel@linuxdriverproject.org; olaf@aepfle.de; apw@canonical.com;
> jasowang@redhat.com; KY Srinivasan <kys@microsoft.com>
> Subject: [PATCH] Drivers: hv: vmbus: fix init_vp_index() for reloading hv_netvsc
> 
> This fixes the recent commit:
> Drivers: hv: vmbus: Further improve CPU affiliation logic
> 
> Without the fix, reloading hv_netvsc hangs the guest.
> 
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> ---
>  drivers/hv/channel_mgmt.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
> index 2f9aead..f61bd07 100644
> --- a/drivers/hv/channel_mgmt.c
> +++ b/drivers/hv/channel_mgmt.c
> @@ -458,6 +458,19 @@ static void init_vp_index(struct vmbus_channel
> *channel, const uuid_le *type_gui
>  			continue;
>  		}
> 
> +		if (cpumask_weight(&primary->alloced_cpus_in_node) ==
> +		    cpumask_weight(cpumask_of_node(primary->numa_node))) {
> +			/*
> +			 * We have cycled through all the CPUs in the node;
> +			 * reset the alloced map.
> +			 * This is necessary because we never clear
> +			 * primary->alloced_cpus_in_node in other places.
> +			 * We need this to "break" the loop when reloading
> +			 * hv_netvsc in SMP guest.
> +			 */
> +			cpumask_clear(&primary->alloced_cpus_in_node);
> +		}
> +
>  		if (!cpumask_test_cpu(cur_cpu,
>  				&primary->alloced_cpus_in_node)) {
>  			cpumask_set_cpu(cur_cpu,
> --

Sorry, please drop the patch.

I shouldn't simply clear primary->alloced_cpus_in_node -- I didn't realize
reloading hv_netvsc doesn't invoke init_vp_index() for the primary channel.

I'll make a V2 patch.

Thanks,
-- Dexuan
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/